The Guadalupe storm petrel (''Hydrobates macrodactylus'') is a small

seabird Seabirds (also known as marine birds) are birds that are adaptation, adapted to life within the marine ecosystem, marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent ...

of the storm petrel

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Hydrobatidae Northern storm petrels are seabirds in the genus ''Hydrobates'' in the Family (biology), family Hydrobatidae, part of the order Procellariiformes. The family was once Lumpers and splitters, lumped with the similar austral storm petrels in the co ...

. It bred only on

Guadalupe Island Guadalupe Island () is a volcanic island located off the western coast of Mexico's Baja California peninsula and about southwest of the city of Ensenada in the state of Baja California, in the Pacific Ocean. The various volcanoes are extinc ...

off

Baja California Baja California, officially the Free and Sovereign State of Baja California, is a state in Mexico. It is the northwesternmost of the 32 federal entities of Mexico. Before becoming a state in 1952, the area was known as the North Territory of B ...

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

, and presumably ranged throughout the region. It has been assessed as

Critically Endangered An IUCN Red List critically endangered (CR or sometimes CE) species is one that has been categorized by the International Union for Conservation of Nature as facing an extremely high risk of extinction in the wild. As of December 2023, of t ...

or possibly

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

Taxonomy

It was formerly defined in the genus ''

Oceanodroma Northern storm petrels are seabirds in the genus ''Hydrobates'' in the family Hydrobatidae, part of the order Procellariiformes. The family was once lumped with the similar austral storm petrels in the combined storm petrels, but have been spl ...

'' before that genus was synonymized with '' Hydrobates''.

Description

This

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

was almost indistinguishable from its relative,

Leach's storm petrel Leach's storm petrel or Leach's petrel (''Hydrobates leucorhous'') is a small seabird of the tubenose order. It is named after the British zoologist William Elford Leach. The scientific name is derived from Ancient Greek. ''Hydrobates'' is from ...

. In the field, they could not be told apart except by their annual rhythm. In the hand, the Guadalupe storm petrel could be distinguished by slightly larger size and the paler underwing coverts. There is no evidence for sexual dimorphism in this species.

Breeding

The breeding season was set between the two other breeding storm petrel species of Guadalupe, the winter-breeding Ainley's and the summer-breeding Townsend's, in accordance with Gause's law. The single egg, white with a faint ring of reddish-brown and

lavender ''Lavandula'' (common name lavender) is a genus of 47 known species of perennial flowering plants in the sage family, Lamiaceae. It is native plant, native to the Old World, primarily found across the drier, warmer regions of the Mediterranean ...

speckles around the blunt end, was laid in burrows maybe 15 in (35–40 cm) long, below the Guadalupe pine (''Pinus radiata'' var. ''binata'')- island oak (''Quercus tomentella'')Contrary to BirdLife International (2012), the birds were not associated with Guadalupe cypress woodland, which only occurs inland and at lower elevations.

cloud forest A cloud forest, also called a water forest, primas forest, or tropical montane cloud forest, is a generally tropical or subtropical, evergreen, Montane forest, montane, Tropical and subtropical moist broadleaf forests, moist forest characteri ...

on top of Mount Augusta. By mid-June, almost all young had already left the burrows. Though little data is available on '' Hydrobates'' breeding, incubation was presumably 42 days or so in this species, just as in similar-sized relatives. Time to

fledging Fledging is the stage in a flying animal's life between hatching or birth and becoming capable of flight. This term is most frequently applied to birds, but is also used for bats. For altricial birds, those that spend more time in vulnerable c ...

must have taken between 60 and 75(−85?) days, most likely around 65 days. This would mean that egg-laying took place from early February to March, and that in April–May, unfledged young were present in most active burrows. Just as in their relatives, the egg was incubated a few days by either parent, after which the other took over, the relieved bird taking to the sea to feed itself for the next incubation stint. The young were fed only at night, also like in other storm petrels.

Call

Its call was described by Walter E. Bryant as sounding something like "here's a letter, here's a letter", with repeated interjections of "For you, for you".

Ecology

Three species of

lice Louse (: lice) is the common name for any member of the infraorder Phthiraptera, which contains nearly 5,000 species of wingless parasitic insects. Phthiraptera was previously recognized as an order, until a 2021 genetic study determined th ...

were found to

parasitize Parasitism is a close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The ento ...

the Guadalupe storm petrel: the menoponids ''Longimenopon dominicanum'' and ''Austromenopon oceanodromae'', and the

ischnocera Ischnocera is a large parvorder of lice from the infraorder Phthiraptera. The parvorder consists of Mallophaga, chewing lice, which feed on the feathers and skin debris of birds. Many species of Ischnocera have evolved an elongated body shape. T ...

n ''Halipeurus raphanus''. The second also occurs on some other storm petrels, and the third was also found on the

ashy storm petrel The ashy storm petrel (''Hydrobates homochroa'') is a small, scarce seabird of the storm petrel family Hydrobatidae. It breeds colonially on islands off the coasts of California and Mexico, and is one of six species of storm petrel that live and ...

. ''L. dominicanum'', though, has to date not been found on other birds and seems to be a case of

coextinction Coextinction and cothreatened refer to the phenomenon of the loss or decline of a host species resulting in the loss or endangerment of another species that depends on it, potentially leading to cascading effects across trophic levels. The term w ...

Status

In January 1885, multiple specimens were collected and described by Walter E. Bryant. The introduction of

cat The cat (''Felis catus''), also referred to as the domestic cat or house cat, is a small domesticated carnivorous mammal. It is the only domesticated species of the family Felidae. Advances in archaeology and genetics have shown that the ...

s to the island decimated the population during the late 19th century. Introduced

goat The goat or domestic goat (''Capra hircus'') is a species of Caprinae, goat-antelope that is mostly kept as livestock. It was domesticated from the wild goat (''C. aegagrus'') of Southwest Asia and Eastern Europe. The goat is a member of the ...

s were also responsible for degradation of the environment. By the end of the 1906 breeding season, it was still considered "abundant", though the "large numbers" of birds present there and then must have been nearly the entire population of this species. Still, it was noted that:

the mortality among these birds from the depredations of the cats that overrun the island is appalling – wings and feathers lie scattered in every direction around the burrows along the top of the pine ridge.

Two specimens were reportedly collected between March 2 and March 5, 1911, and the last record of a breeding bird was in 1912. The species has not been seen since. Only old, abandoned burrows and the decayed remains of storm petrels killed by cats were found in the years thereafter. However, the Guadalupe storm petrel cannot be distinguished from the

sympatric In biology, two closely related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter each other. An initially interbreeding population that splits into two or more distinct spe ...

''H. cheimomnestes/socorroensis'' in the field, and surveys on Guadalupe invariably took place outside the breeding season of ''H. macrodactyla'', focusing on researching the local Leach's storm petrels. Thus, some hope remained for the present species' survival, or rather, its extinction could not be definitely confirmed. Guadalupe storm petrel in Scotland

From June 4 to June 10, 2000, the Guadalupe storm petrel's breeding grounds were finally surveyed at the correct time. Had the species survived, not only would recently fledged immature birds have been present, but also all signs of a recently ended breeding season, such as eggshells and freshly used burrows retaining the musky smell of these birds. In the words of the expedition's primary researcher,

Exequiel Ezcurra Exequiel Ezcurra (born March 21, 1950, Buenos Aires, Argentina) is an Argentine-Mexican plant ecologist and conservationist. His highly interdisciplinary work spans desert plant ecology, mangroves, island biogeography, sea birds, fisheries, ocea ...

of the

San Diego Natural History Museum The San Diego Natural History Museum is a museum in Balboa Park in San Diego, California. It was founded in 1874 as the San Diego Society of Natural History. It is the second oldest scientific institution west of the Mississippi and the oldest ...

We searched thoroughly for the Guadalupe storm petrel, and failed to find it. Sadly, we are now more ready to admit that the species is indeed extinct. Never, since the 1920s, had so much search effort been devoted to this species. At different times, more than 10 researchers looked for the elusive creature. It simply was not there.

The official classification by the

IUCN The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...

has not been updated yet. In any case, the

precautionary principle The precautionary principle (or precautionary approach) is a broad epistemological, philosophical and legal approach to innovations with potential for causing harm when extensive scientific knowledge on the matter is lacking. It emphasizes cautio ...

would probably require a few years of follow-up surveys, possible now that restoration of Guadalupe's ecosystem is underway. Despite the species' likely extinction, the two other storm-petrel species that are also endemic breeders to Guadalupe - Townsend's and Ainley's storm petrels - still survive on offshore islets.

Notes

References

External links

Species factsheet
- BirdLife International {{Taxonbar, from=Q940820

Guadalupe storm petrel The Guadalupe storm petrel (''Hydrobates macrodactylus'') is a small seabird of the storm petrel family (biology), family Hydrobatidae. It bred only on Guadalupe Island off Baja California, Mexico, and presumably ranged throughout the region. It ...

Birds of Mexico